A plasma can be loosely defined as a physical system containing many mobile charged particles (electrons and ions). Plasmas are ionized gases and are often referred to
as "the fourth state of matter."
The pictures to the right show different plasma states in a laboratory and in nature.
Visual displays from electrical discharges such as in fluorescent lamps, neon lights, and lightning storms are due to the creation of plasmas. The terrestrial ionosphere and magnetosphere - Earth's evironment at altitudes of 70 km and higher - is a plasma. The ionosphere is useful in radio communications. The solar wind is a plasma ejected from the Sun into the interplanetary space. Its interaction with the Earth's plasma produces aurora borealis. The stellar interior and atmosphere, including the Sun's, is in a plasma state. The interstellar space consists of plasma. Plasma phenomena occur in nebulae, supernovae remanents, pulsars, and other astrophysical objects.
On Earth an important application of plasma physics being pursued is the large scale production of environmentally friendly energy - thermonuclear fusion energy. MIT's Plasma Science and Fusion Center is a globally prominent player in this research effort.
This course introduces some of the basic concepts needed to study and understand the behavior of plasmas in a variety of environments. |
